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Retrocommissioning Works

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Eveline Killian and Daniel Tuhus-Dubrow from Cx Associates, Christopher Vintinner from Distech Controls, and John Grosvenor from Vermont Historical Society presented these slides at the 2018 Better Buildings by Design conference. The presentation discusses what retrocommissioning is/is not, along with a case study at the Vermont Historical Society. This presentation gives a unique look into retrocommissioning processes and achievements by discussing an owner's perspective.

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Retrocommissioning Works

  1. 1. Experience in Retrocommissioning Eveline Killian Daniel Tuhus-Dubrow Christopher Vintinner John Grosvenor Cx Associates Cx Associates Distech Controls Vermont Historical Society Presented by:
  2. 2. Agenda What is Retrocommissioning? The RCx program in Vermont Vermont Historical Society Case Study  Issues  Implemented Measures  Beyond Retrocommissioning  Impact of Measures  Project Economics Typical RCx Measures Team is Critical
  3. 3. Retrocommissioning is…..
  4. 4. Retrocommissioning is NOT….. Capital improvement projects: However… Equipment at the end of its useful life will often be identified through the RCx process. Lighting retrofits Equipment replacement Window upgrades
  5. 5. Typical RCx Measures • Unnecessary power consumption • Simultaneous heating and cooling • Calibrating thermostats and sensors • Replacing worn parts (belts and valves) • Optimization • Air balancing systems • Economizers • Controls sequences • Variable-frequency drive speed
  6. 6. RCx from Controls Contractor Perspective An Exciting opportunity to showcase the benefits of a Building Automation System • Visualization & Graphical User interface • Control • Optimization • Measurement and Verification
  7. 7. Retrocommissioning to the Owner Maintenance for existing equipment Improved equipment and systems function Reduced operational costs (10-20%) Addressing VHS structural deficits Reduced energy use from deferred maintenance (30-60%)
  8. 8. Reducing Greenhouse Gas Emissions Commercial buildings consume nearly half of the building energy used in the United States (20% of total U.S. energy consumption and greenhouse gas emissions) Potential for Existing Buildings Saving Money Median whole building energy savings of 16% Median payback time of 1.1 years
  9. 9. The RCx Process in Vermont Programs from Efficiency Vermont and BED Qualify Develop Implement Verify
  10. 10. Steps in Qualifying Phase Pre-qualify Walkthrough by team Findings and Recommendations Estimate energy savings
  11. 11. Case Study Vermont Historical Society Barre, Vermont
  12. 12. Project Timeline Baseline Established December 2, 2016 April 3, 2017 RCx Complete Steam Humidifiers Installed August 2017 September 2017 LED Lighting Installed
  13. 13. Vermont Historical Society Pre-RCx Building Demand Profile 35 40 45 50 55 60 65 70 75 80 85 BuildingDemand(kW) Hour of DaySun Mon Tue Wed Thu Fri Sat Hol
  14. 14. Pre-Existing Conditions • Nuisance alarms • Bad sensors • Climate control set points • Hot and cold pockets in building. • Humidification not keeping up • Heating/cooling overshooting temps • Manual changes to lead pumps and boilers Problems: • Reactive maintenance vs. preventive/predictive • Deferred maintenance • Design deficiencies Causes: System wasn’t satisfactory or energy efficient!
  15. 15. Implemented Measures Avoiding Simultaneous Operation of: Chiller and Dry Cooler Both Boilers Trim & Respond Reset a.Chille r Pumps a.Boiler Pumps AHU-2 Fan Speed Sensor Calibration Chilled Water Temp. Boiler Water Temp. T-stats AHU Air Temp. Reset Schedule Boiler to Outside Air Temp. VAV Damper Position to AHU Supply Air Temp. Office Setpoints and Schedules Corrected Minimum Ventilation
  16. 16. Avoided Simultaneous Operation Avoiding Simultaneous Operation of: Chiller and Dry Cooler Both Boilers
  17. 17. Chiller & Dry Cooler
  18. 18. Chiller & Dry Cooler
  19. 19. Boilers
  20. 20. Boilers
  21. 21. Trim & Respond Reset Avoiding Simultaneous Operation of: Chiller and Dry Cooler Both Boilers Trim & Respond Reset Chiller Pumps Boiler Pumps AHU-2 Fan Speed
  22. 22. Chiller Pumps
  23. 23. Chiller Pumps
  24. 24. Boiler Pumps
  25. 25. Boiler Pumps
  26. 26. AHU-2 Static Pressure Reset
  27. 27. AHU-2 Static Pressure Reset
  28. 28. Sensor Calibration Avoiding Simultaneous Operation of: Chiller and Dry Cooler Both Boilers Trim & Respond Reset Chiller Pumps Boiler Pumps AHU-2 Fan Speed Sensor Calibration Chilled Water Temp. Boiler Water Temp. T-stats AHU Air Temp.
  29. 29. Sensor Calibration BMS Sensor Reads 43% RH Calibration sensor reads 47.6% RH Damaged Probe
  30. 30. Reset Schedules Avoiding Simultaneous Operation of: Chiller and Dry Cooler Both Boilers Trim & Respond Reset Chiller Pumps Boiler Pumps AHU-2 Fan Speed Sensor Calibration Chilled Water Temp. Boiler Water Temp. T-stats AHU Air Temp. Reset Schedule Boiler to Outside Air Temp. VAV Damper Position to AHU Supply Air Temp.
  31. 31. Boiler Reset Schedule
  32. 32. Office Setpoints and Schedules Avoiding Simultaneous Operation of: Chiller and Dry Cooler Both Boilers Trim & Respond Reset Chiller Pumps Boiler Pumps AHU-2 Fan Speed Sensor Calibration Chilled Water Temp. Boiler Water Temp. T-stats AHU Air Temp. Reset Schedule Boiler to Outside Air Temp. VAV Damper Position to AHU Supply Air Temp. Office Setpoints and Schedules
  33. 33. Office Setpoints & Schedules
  34. 34. Office Setpoints & Schedules
  35. 35. Corrected Minimum Ventilation Avoiding Simultaneous Operation of: Chiller and Dry Cooler Both Boilers Trim & Respond Reset a.Chiller Pumps a.Boiler Pumps AHU-2 Fan Speed Sensor Calibration Chilled Water Temp. Boiler Water Temp. T-stats AHU Air Temp. Reset Schedule Boiler to Outside Air Temp. VAV Damper Position to AHU Supply Air Temp. Office Setpoints and Schedules Corrected Minimum Ventilation
  36. 36. Ventilation
  37. 37. Post RCx Capital Improvements • Steam humidifiers and LED lighting replacement
  38. 38. The Outcome – Demand Impacts 20 30 40 50 60 70 80 90 100 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 BuildingDemand(kW) Outside Air Temperature Occupied Pre Occupied Post
  39. 39. Impact on Daily Load Profile 35 40 45 50 55 60 65 70 75 80 85 12:00 AM 1:00 AM 2:00 AM 3:00 AM 4:00 AM 5:00 AM 6:00 AM 7:00 AM 8:00 AM 9:00 AM 10:00 AM 11:00 AM 12:00 PM 1:00 PM 2:00 PM 3:00 PM 4:00 PM 5:00 PM 6:00 PM 7:00 PM 8:00 PM 9:00 PM 10:00 PM 11:00 PM BuildingLoad(kW)
  40. 40. 2016 – 2017 Utility Comparison
  41. 41. RCx Project Economics $(15,000.00) $(5,000.00) $5,000.00 $15,000.00 $25,000.00 $35,000.00 $45,000.00 $55,000.00 1 2 3 4 5 Year Investment Savings Cumulative
  42. 42. Outcome from the Owner’s Perspective No more nuisance alarms Systems respond appropriately to weather conditions Set points maintained Improved energy efficiency lead to other conservation projects Cost savings Noticed by the occupants and Facilities Manager
  43. 43. Other Retrocommissioning Experiences
  44. 44. Throttled Valves
  45. 45. Equipment Overrides
  46. 46. Operating Schedules
  47. 47. Damaged Sensors
  48. 48. Teamwork Have the right people! Team Commissioning Engineer Controls Contractor Facilities Staff Introduce Perspectives Brainstorm Identify Opportunities Evaluate Merit
  49. 49. Thank You! Eveline Killian Associate Principal Cx Associates Burlington, VT 802-861-2715 x15 eveline@cx-assoc.com Daniel Tuhus-Dubrow Senior Engineer Cx Associates Burlington, VT 802-861-2715 x21 daniel@cx-assoc.com Chris Vintinner Sales Support Engineer Distech Controls, Inc. 802-922-0039 cvintinner@distech-controls.com www.distech-controls.com John Grosvenor Director of Finance and Operations Vermont Historical Society Barre, VT 802-479-8513 john.grosvenor@vermonthistory.com

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